Vertical rise per bp of B-DNA is

Options

A. `3.3 A`
B. `3.8 A`
C. `3.4 A`
D. `2.56 A`

Answer

To find the vertical rise per base pair of B-DNA, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding B-DNA Structure**:
- B-DNA is the most common form of DNA in cells. It consists of two strands that coil around each other to form a double helix.

2. **Base Pair Distance**:
- The distance between adjacent base pairs in B-DNA is known to be approximately 3.4 Å (Angstroms). This is the distance measured vertically from one base pair to the next.

3. **Rotation per Base Pair**:
- Each complete turn of the DNA helix consists of about 10 base pairs and spans a distance of 34 Å. This means that for every complete turn of the helix, the DNA rises vertically by 34 Å.

4. **Calculating Vertical Rise per Base Pair**:
- To find the vertical rise per base pair, we can divide the total rise per turn by the number of base pairs per turn:
\[ \text{Vertical Rise per Base Pair} = \frac{\text{Total Rise per Turn}}{\text{Number of Base Pairs per Turn}} = \frac{34 \, \text{Å}}{10} = 3.4 \, \text{Å} \]

5. **Conclusion**:
- Therefore, the vertical rise per base pair of B-DNA is 3.4 Å.

### Final Answer:
The vertical rise per base pair of B-DNA is **3.4 Å**.

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